STRUCTURAL STYLE AND GEODYNAMIC EVOLUTION OF CAMARGUE AND WESTERN PROVENCAL BASIN, SOUTHEASTERN FRANCE

We present a tectonic analysis of the Camargue and Western Provencal m argin based on geophysical maps, seismic profiles, and well log data. The tectonic style results from a polyphase geological history. Mesozo ic extension was followed by Late Cretaceous-Eocene compression. Durin g Oligocene extension, part of the preexisting compressional structure s was reactivated along extensional detachments. The concept of Oligoc ene negative inversion is applied to an asymmetrical opening of the no rthwestern Mediterranean basin. The steep Provencal margin is separate d from the extended Gulf of Lion margin by a major transfer zone. The extensional structures of the Gulf of Lion can be placed in the framew ork of the Western European rift system. Late Eocene-early Oligocene E -W extension is followed by NE-SW late Oligocene-early Aquitanian open ing of previous transverse structures. Seismic evidence supports a pos sible eastward extension of the North Pyrenean fault.